So, I'd love to have werewolves in the world I'm building, but as it's a sci-fi setting I don't really want them to be magical. I can stomach some pseudoscience, but I want the process to be as realistic as possible. To this end, I've removed the influence of the moon (it's just a cyclic transformation, happens based on an internal clock), silver bullets and holy water don't have any special potency, and I'd be willing to extend the transformation from man to werewolf to an entire day, or even a week if necessary. What I'd like to know now is what sorts of preparations a lycanthrope would have to go through in order to make this transformation seem plausible, if not entirely possible.

For instance, what would someone have to eat to support an increase in size, a reconfiguration of bone and muscle structure, and an extensive growth of hair? What sorts of exercises or therapies might be useful or necessary to help people through this painful process? Are there perhaps any good examples of animals that do something like this, and how do they prepare for it?